Ephesians 1:4 Just as He chose us in Him before the foundation of the world, that we should be holy and without blame before Him in love.
Before you were born, God knew that you would do things you would later regret, but He had a plan to present you blameless, and holy, regardless of your past. He is doing that now, but will completely fulfill that plan in your life in the days to come. If the enemy tries to tell you that you are not good enough because of all the times you have messed up.
Don’t believe him, instead remind him of his future. You are considered blameless because God not only has forgiven your past, but He doesn’t hold it against you any more. This is something to rejoice about, because there is nothing you could have done to deserve salvation. Remember, Jesus paid it all for you, so now God looks at you without blame. Several times today, thank the Lord for enabling you to be blameless.